Anatomy & Physiology: Tissues, Skin, and Integumentary System Study Guide

Tissues of the Human Body

Overview of Tissue Types

The human body is composed of four primary tissue types: epithelial, connective, muscle, and nervous tissue. Each type has distinct structures and functions essential for maintaining homeostasis and supporting life.

• Epithelial Tissue: Covers body surfaces, lines cavities, and forms glands.

• Connective Tissue: Supports, binds, and protects organs.

• Muscle Tissue: Responsible for movement.

• Nervous Tissue: Conducts electrical impulses and processes information.

Epithelial Tissue

Epithelial tissue forms protective barriers and is involved in absorption, secretion, and sensation. It is classified by cell shape and number of layers.

• Simple Squamous: Single layer of flat cells; found in lungs, blood vessels (endothelium), and body cavities (mesothelium).

• Stratified Squamous: Multiple layers; found in skin (epidermis), esophagus.

• Simple Cuboidal: Cube-shaped cells; found in kidney tubules, glands.

• Stratified Cuboidal: Multiple layers of cuboidal cells; found in mammary glands.

• Transitional Epithelium: Specialized for stretching; found in bladder.

• Simple Columnar: Tall, column-like cells; found in digestive tract.

• Pseudostratified Columnar: Appears layered but all cells touch basement membrane; found in trachea and airways.

Key Functions:

• Absorption: e.g., cells lining gut or kidney tubules.

• Protection: e.g., stratified squamous of the skin.

• Secretion: e.g., glandular epithelium (lacrimal glands).

Glands

Glands are specialized epithelial structures that produce and release substances.

• Exocrine Glands: Release secretions into ducts (e.g., sweat, salivary, mammary glands).

• Endocrine Glands: Release hormones directly into the blood (e.g., pituitary, thyroid, adrenal glands).

Modes of Secretion:

• Merocrine: Exocytosis (e.g., sweat glands).

• Apocrine: Part of cell pinched off (e.g., mammary glands).

• Holocrine: Cell ruptures (e.g., sebaceous glands).

Connective Tissue

Types and Functions

Connective tissue provides structural support, stores energy, and connects other tissues. It is classified into three main types:

• Fibrous Connective Tissue: Includes loose (areolar, reticular) and dense (tendons, ligaments).

• Supportive Connective Tissue: Cartilage (hyaline, elastic, fibrocartilage) and bone (spongy, compact).

• Fluid Connective Tissue: Blood and lymph.

What are the two cell types? 

Key Cells:

• Fibroblasts: Produce extracellular fibers and ground substance.

• Adipocytes: Store fat.

• Chondrocytes: Cartilage cells.

• Osteocytes: Bone cells.

• Keratinocytes: Epidermal cells producing keratin.

• Melanocytes: Produce melanin pigment.

Types of Fibers:

• Collagen: Strong, flexible, resists stretching.

• Elastic: Stretch and recoil.

• Reticular: Thin, branching, supportive networks.

Intercellular Connections

• Tight Junctions: Prevent leakage between cells.

• Gap Junctions: Allow communication between cells.

• Desmosomes: Anchor cells together.

• Hemidesmosomes: Attach cells to basement membrane.

Appositional vs interstitial: Appositional- adds layers to surface. Interstitial- enlarges from within.  

Types of bone tissue: Compact and Spongy bone.  

Four types of tissue membranes:  

Mucous Membranes - line “exterior” passageways 

Serous Membranes - line body cavities, delicate 

Cutaneous Membrane - covers body, dry 

Synovial Membrane - moveable joint cavities 

 

Muscle Tissue

Types and Characteristics

Muscle tissue is specialized for contraction and movement. There are three types:

• Skeletal Muscle: Voluntary, long cylindrical, striated, multinucleate; attached to bones.

• Cardiac Muscle: Involuntary, short, branched, striated, uninucleate, intercalated discs; found in heart.

• Smooth Muscle: Involuntary, short, spindle-shaped, non-striated, uninucleate; found in walls of viscera.

Unique Features:

• Skeletal: Voluntary control, rapid contraction.

• Cardiac: Intercalated discs for synchronized contraction.

• Smooth: Slow, sustained contraction.

Nervous Tissue

Structure and Function

Nervous tissue is responsible for sensing stimuli and transmitting signals. It consists of two main cell types:

• Neurons: Conduct electrical impulses; major parts include cell body, axon, dendrites.

• Neuroglia: Support, protect, and nourish neurons.

Integumentary System

Overview and Functions

The integumentary system includes the skin, hair, nails, and glands. It protects the body, regulates temperature, and provides sensory information.

• Protection: Barrier against pathogens, UV radiation, and physical injury.

• Regulation: Controls body temperature and water loss.

• Sensation: Detects touch, pressure, pain, and temperature.

• Vitamin D Production: Synthesized in skin upon exposure to sunlight.

Skin Structure

• Epidermis: Outermost layer; avascular; composed of keratinized stratified squamous epithelium.

• Dermis: Connective tissue layer beneath epidermis; contains blood vessels, nerves, glands.

• Subcutaneous (Hypodermis): Loose connective tissue and fat below dermis; insulates and cushions.

Layers of the Epidermis

• Stratum Basale: Deepest layer; mitotically active cells.

• Stratum Spinosum: Provides strength and flexibility.

• Stratum Granulosum: Keratinization begins.

• Stratum Lucidum: Present only in thick skin (palms, soles).

• Stratum Corneum: Outermost layer; dead, keratinized cells.

Accessory Structures

• Hair: Provides protection and sensory input.

• Nails: Protect fingertips and enhance sensation.

• Glands: Sweat (thermoregulation), sebaceous (lubrication), mammary (milk production).

Skin Color

• Melanin: Brown-black pigment produced by melanocytes.

• Carotene: Yellow-orange pigment from diet.

• Hemoglobin: Red pigment from blood.

Touch Receptors

• Epidermis: Tactile discs (texture).

• Dermis: Free nerve endings (touch, pressure), Lamellar (Pacinian) corpuscles (deep pressure, vibration), Bulbous (Ruffini) corpuscles (stretching).

Burns

Burns are injuries caused by heat, chemicals, electricity, or radiation. Severity is classified by depth and area affected.

• First-Degree: Partial thickness; affects epidermis; redness, pain.

• Second-Degree: Partial thickness; affects epidermis and some dermis; blistering, pain, swelling.

• Third-Degree: Full thickness; affects epidermis, dermis, and hypodermis; skin regeneration destroyed, may require grafting.

Complications: Dehydration, infection, electrolyte imbalance.

Skin Regeneration and Aging

• Repair: Involves regeneration of epidermis and dermis.

• Vitamin D3 Production: Essential for calcium absorption.

• Aging: Skin thins, loses elasticity, hair grays, nails become brittle.

Membranes

Types of Body Membranes

Membranes line body cavities and surfaces, providing protection and lubrication.

Membrane Type	Location	Function
Mucous	Lines exterior passageways (e.g., digestive, respiratory)	Secretes mucus, protects, lubricates
Serous	Lines body cavities (e.g., pleura, pericardium, peritoneum)	Secretes serous fluid, reduces friction
Cutaneous	Covers body (skin)	Protection, sensation
Synovial	Lines joint cavities	Secretes synovial fluid, lubricates joints

Key Skills for Exam Preparation

• Recognize different epithelial tissue types.

• Differentiate between burn types.

• Sequence the events of skin regeneration.

• Differentiate between four main tissue types.

• Identify and describe major microscope types and their uses.

• Sequence events of tissue injury.

• Compare and contrast three muscle types.

• Describe the layers of the epidermis and dermis.

Study Tips

• Review end-of-chapter questions.

• Use interactive resources and quizzes.

• Make flashcards for key terms and concepts.

• Draw and label diagrams.

• Practice sequencing processes aloud or in writing.

Additional info: Some explanations and classifications have been expanded for clarity and completeness based on standard Anatomy & Physiology curriculum.